jan-gustav werthen 1 st cpv china & 4 th international cpv workshop september 17 – 18, 2012...
TRANSCRIPT
Jan-Gustav Werthen
1st CPV China & 4th International CPV WorkshopSeptember 17 – 18, 2012
JDSU 6” Wafer CPV Cells
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Outline
The value of MQW for CPV• Theory & Modeling
JDSU 42% MQW Cells• Qualified production cells
Performance Roadmap Summary
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There are no ternary alloys lattice matched to Ge or GaAs with a lower bandgap than GaAs
The Value of Multiple Quantum Wells (MQW)
InGaP/GaAs
The GaInP and GaAs bandgaps in a tandem/triple junction are too high.
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GaAs Band Gap not ideal
• GaAs bandgap energetically too high• InGaAs better suited for AM1.5 spectrum under concentration
GaAsIn0.1GaAs
1000 Suns
J. Ward et al, 23rd IEEE PVSC, 650-654 (1993)
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Lattice Mismatch in Bulk InGaAs Leads to Dislocations
Dislocations
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GaAsP (barrier)
InGaAs (well)
GaAs (bulk)
We are able to grow up to 65 quantum wells with this technique
‘Strain balanced’ quantum well solar cells are dislocation free
EF
Stress Balancing Avoids the Creation of Dislocations
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Generation and Recombination with MQWs in Cell Junction
p i
Sh
ock
ley
Inje
ctio
n
Re
com
bin
atio
n
Re
com
bin
atio
n
Δμ
n
Thermal escape
Thermal escape
Ge
ne
ratio
n
At short circuit current all generated carriers escape from the wells
GaAsGaAsP
InGaAs
© 2012 JDS Uniphase Corporation | JDSU CONFIDENTIAL AND PROPRIETARY INFORMATION
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MQW Cell Spectral Response: Modeling and Experiment
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JDSU Production MQW CPV Cells: Spectral Response
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Typical Performance Parameters Production MQW Cells
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Highest Performing Production MQW Cells
High-Efficiency Cell (9.3mm x 9.3mm)
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Distribution (Efficiency and Current at max power)
Data shown for 9.3mm x 9.3mm cells
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Temperature Coefficients
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MQW Cell Platform Fully Qualified
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MQW Cell Performance Roadmap
2012
41%*2014
42%2015
43%
InGaP MQW MQW
2013
41.5%
AlInGaP
6 inch wafer
AlGaAs
GeGe
MQW MQW MQW
Ga(In)As
GeGe
*Minimum average efficiency from the first available production cells
This roadmap contains forward-looking product development plans based on current expectations. The actual products, product functionality, and timing of the product and or product functionality releases could change materially.
© 2012 JDS Uniphase Corporation | JDSU CONFIDENTIAL AND PROPRIETARY INFORMATION
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Summary
MQW CPV Cells Perform as Expected• Median cell efficiency at 41.5% per wafer
JDSU MQW Cell Platform Established• Qualified production cells on 150mm (6”) wafers
Roadmap Expands the Use of MQWs • Add MQWs to top cell to reach 43% per wafer
Acknowledgements to the JDSU engineering team:Ben Browne, Jon Lacey, James Liu, Xiaodong Chen,
Ta-Chung Wu, Gianluca Bacchin, Tom Tibbits
